JPH10327626A - Hydraulic circuit of sulky type rice transplanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit of a sulky type transplanter, capable of making flow rate constant, preventing the action of each hydraulic actuator from becoming sensitive, and improving straightness by connecting the first and second flow rate controlling valves in a serial state to a discharging side of a hydraulic pump directly connected to an engine. SOLUTION: The first and second flow rate regulating valves 31 and 32 are connected in a serial state to the discharging side of a hydraulic pump P directly connected to an engine 30. Further, preferably, a right and left tilt- control valve 33 for controlling right and left tilt of a transplanting device us connected between the first and second flow rate control valves 31 and 32, and a power steering valve 34 and lifting and lowering control valve 35 are connected to the downstream side of the first and second flow control valves 31 and 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydraulic circuit for a riding rice transplanter.

[0002]

2. Description of the Related Art Conventionally, in a riding rice transplanter, the control of raising and lowering of the planting portion and the right and left inclination are performed by hydraulic pressure, and power steering by hydraulic pressure has recently become widespread.

[0003]

However, since the hydraulic pump is directly connected to the engine, as shown in FIG. 4, the discharge amount of hydraulic oil from the hydraulic pump is proportional to the engine speed. In the case of a riding rice transplanter, the operation of each hydraulic actuator becomes too sensitive because the engine keeps high rotation during planting work.For example, in the case of power steering, the operating force of the steering wheel becomes extremely light, and There is a problem that becomes worse.

[0004]

Therefore, according to the present invention, a first and second flow control valves are connected in series to the discharge side of a hydraulic pump directly connected to an engine. No circuit is provided.

[0005] The present invention also has the following features.

A left-right inclination control valve for controlling the left-right inclination of the planting portion is connected between the first and second flow control valves, and a power steering valve and a power steering valve are provided downstream of the first and second flow control valves. Connected with a lifting control valve that controls the raising and lowering of the planting part.

[0007] A second flow control valve is interposed between the hydraulic pump and the power steering valve to regulate the upper limit of the flow rate of hydraulic oil supplied to the power steering valve.

The opening of the power steering valve is regulated in inverse proportion to the running speed of the vehicle body.

The return port of the power steering valve and the bleed-off port of the second flow control valve are connected via a bypass oil passage.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, first and second flow control valves are connected in series on the discharge side of a hydraulic pump directly connected to an engine, and are implanted between the first and second flow control valves. A left-right inclination control valve for controlling the left-right inclination of the section is connected, and a power steering valve for controlling a hydraulic pressure for assisting the steering force and a control for raising and lowering the planting section are provided downstream of the first and second flow control valves. A lifting / lowering control valve is connected, and a flow dividing valve from a hydraulic pump is interposed between the lifting / lowering control valve and the power steering valve to maintain a constant flow rate of hydraulic oil supplied to each control valve and to send the hydraulic oil to the power steering valve. The upper limit of the flow rate of hydraulic oil to be supplied is made constant, and the priority order of hydraulic oil flow control is set in the order of the left / right tilt control valve, the power steering valve, and the elevation control valve.

Further, the return port of the power steering valve and the bleed-off port of the second flow control valve are connected via a bypass oil passage, so that excess pressurized oil from the power steering is used for lifting and lowering the work equipment. Like that.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a riding rice transplanter A equipped with a hydraulic circuit H according to the present invention. In the riding rice transplanter A, a three-point link mechanism C is provided behind a self-propelled traveling body B. Through
The planting device D is connected so as to be able to move up and down and tilt left and right.

The traveling vehicle body B has left and right front wheels 2L and 2R attached to the front left and right sides of the vehicle body frame 1 so as to be steerable and rotatable. , 3R, and a vehicle body side hitch 8 for connecting the prime mover unit 4, the driving unit 5, the seat 6, the lifting mechanism 7, and the planting device D is arranged on the upper surface of the vehicle body frame 1 from the front in the above order. The power from the prime mover unit 4 is transmitted to the left and right front and rear wheels 2L, 2R, 3L, 3R via the continuously variable transmission 9, the transmission case 10, and the front and rear differential cases 11, 12, and is erected on the operation unit 5. Left and right front wheels 2L, 2R by turning operation of steering wheel 13
To steer.

The three-point link mechanism C comprises a top link 14 and a left and right lower link 15. The front ends of the top link 14 and the left and right lower link 15 are rotatably connected to the rear surface of the vehicle-side hitch 8. The rear end is rotatably connected to the planting side hitch 16 to form a parallel link mechanism. The lifting hydraulic cylinder 17 arranged on the vehicle body side hitch 8 is connected to a lift arm 18.
, And is linked to the left and right lower links 15 through the extension and retraction of the hydraulic cylinder 17 to raise and lower the planting device D. In the figure, reference numeral 19 denotes a spare seedling stand, and E denotes a side-strip fertilizer capable of folding both side ends forward.

In the planting device D, a transmission case 22 also serving as a planting section frame is pivotally attached to the planting side hitch 16 via a pivot 21 extending in the front-rear direction so as to be tiltable left and right.
A seedling table 23 inclined forward and rearwardly high is disposed above the seedling table 22, and a planting claw driven by the transmission case 22 near the lower end edge of the seedling table 23.
The arrangement is such that the seedlings placed on the seedling mounting table are planted on the rice field by rotating the planting claws.

A left-right tilt cylinder 26 is interposed between a stay 25 extending upward from the upper surface of the planting side hitch 16 and the seedling mounting table 23. The planting device D is inclined left and right with respect to the running vehicle body B. In the figure, 27 is a center float, and 28 is a side float.

FIG. 2 shows a hydraulic circuit H in which a first flow control valve 31 and a second flow control valve 32 are connected in series in the above-described order at the discharge port of a hydraulic pump P interlocked with the engine 30. Connected to

The left and right tilt control valve 33 is connected to the outlet port 31a of the first flow control valve 31, the second flow control valve 32 is connected to the bleed-off port 31b of the first flow control valve 31, and the second A power steering valve 34 connected to the steering wheel 13 is connected to an outlet port 32a of the flow control valve 32, and an elevation control valve 35 is connected to a bleed-off port 32b of the second flow control valve 32. The return port 34r of the power steering valve 34 is connected to the bleed-off port 32b of the second flow control valve 32 via a bypass oil passage 36.

The power steering valve 34 and the elevation control valve 35
Is a PT open type, the left and right tilt control valve 33 is an open center type, and the first and second flow control valves 31, 32 are
A throttle 38 and a shunt valve 39 are connected in parallel to the inflow port 37,
The upstream and downstream sides of the throttle 38 are each connected to a pilot oil passage.
By connecting the throttle 38 to the diverter valve 39 via 40 and controlling the degree of opening of the diverter valve 39 by the differential pressure due to the flow rate of the hydraulic oil, the first
-The flow rate of the hydraulic oil flowing out of the second flow control valves 31 and 32 is kept constant.

In FIG. 2, 41 is a hydraulic oil tank, 42 is a filter, 43 is a relief valve, 44 is a check valve, 45 is a manual valve, 46
Is a speed controller, and 47 is a negative pressure prevention circuit.

With the above configuration, as shown in FIG. 4, even when the engine 30 rotates at a high speed, the upper limit of the flow rate of the hydraulic oil to the left / right tilt control valve 33, the power steering valve 34, and the elevation control valve 35 is increased. Since the set values of the first and second flow control valves 31 and 32 are regulated and no oil pressure equal to or higher than the set pressure of the relief valve 43 acts, the operation of each hydraulic actuator is prevented from becoming too sensitive.

When the power steering valve 34 is closed, the pressure oil that has passed through the power steering valve 34 is supplied to the elevation control valve 35, so that the capacity of the elevation mechanism 7 can be enhanced. .

When the engine 30 is running at a low speed, the flow rate of the pressure oil discharged from the hydraulic pump P is small, and when all the hydraulic actuators are operated simultaneously, the operation becomes unstable. First, pressure oil is supplied to the left / right tilt control valve 33, and if there is remaining power, pressure oil is supplied to the power steering valve 34, and if there is remaining power, pressure oil is supplied to the elevation control valve 35, and Control valve 33, power steering valve
34, the priority order of the elevation control valve 35 is set.

FIG. 3 shows a steering mechanism S. The steering mechanism S includes a steering wheel 13.
, Steering shaft 50, steering gear box 51, steering arm 52, left and right tie rods 53L, 53R
The left and right front wheels 2L, 2R are interlockingly connected via left and right knuckle arms 54 and left and right king pins 55, and in this embodiment,
Steering shaft 50 and steering arm 52,
The steering wheel 13 is hydraulically connected with the mechanical operation transmission system and the hydraulic operation transmission system, which are provided in parallel.
The effort required for operation is reduced. Therefore, the force required for operating the steering wheel 13 is substantially proportional to the delay in the operation of the hydraulic operation transmission system with respect to the mechanical operation transmission system and the rigidity of the mechanical operation transmission system.

In the mechanical operation transmission system, a planetary gear mechanism is provided in the steering gear box 51, a sun gear of the planetary gear mechanism is fixed to a steering shaft 50, and a steering arm is mounted on a frame supporting the planetary gear. 52 base ends are fixed.

The hydraulic operation transmission system includes a power cylinder 61 interposed between the steering arm 52 and the vehicle body frame 1, the power cylinder 61 being connected to the power steering valve 34, and an expansion and contraction operation of the power cylinder 61. The steering arm 52 is rotated.

The ring gear 56 of the planetary gear mechanism is used.
r is linked to the spool of the power steering valve 34, and a ring gear 56r is provided with a play in a rotating direction, which will be described later. The reaction force of the operating force acting on the ring gear 56r causes the play in proportion to the play amount. The mechanical operation transmission system and the hydraulic operation transmission system are interlocked by operating the spool.

Further, a substantially trapezoidal concave portion 57 is formed on the outer periphery of the ring gear 56r, and a stopper 58 having a substantially trapezoidal tip at the outer wall of the steering gear box 51.
The stopper 58 is slidably inserted to allow the trapezoidal portion 58a formed at the tip of the stopper 58 to be inserted into the recess 57, and the stopper 58 is connected to the stepless speed changer via a bell crank 59 and a wire 60. When the speed change lever is operated at a high speed, the amount of insertion of the trapezoidal portion 58a into the recess 57 increases, and the play, that is, the spool Since the operation amount decreases, the operation speed of the power cylinder 61 decreases, and the operation delay of the hydraulic operation transmission system with respect to the mechanical operation transmission system increases,
The force required for operating the steering wheel 13 is increased, and the straightness during high-speed running is improved. The ring gear 56
A restoring urging force is applied to r so that the ring gear 56r maintains the neutral position when the operating force from the steering wheel 13 is not applied.

[0030]

According to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, the first and second flow control valves are connected in series to the discharge side of the hydraulic pump directly connected to the engine, so that the flow rate of the hydraulic oil supplied to each hydraulic actuator is increased. Becomes constant, and the operation of each hydraulic actuator can be prevented from becoming too sensitive at the time of high engine rotation.

According to the second aspect of the present invention, the first and the second
A left-right inclination control valve for controlling the left-right inclination of the planting portion is connected between the flow control valves, and a power steering valve and an elevating device for controlling the elevation of the planting portion are provided downstream of the first and second flow control valves. By connecting to the control valve, the priority order of flow control at low engine speed can be changed to left / right tilt control, power steering,
It can be set in the order of ascending and descending of the planting section.

According to the third aspect of the present invention, a second flow control valve is provided between the hydraulic pump and the power steering valve to regulate the upper limit of the flow rate of the working oil supplied to the power steering valve. Thus, even when the engine is running at a high speed, a constant flow rate of pressure oil is supplied to the power cylinder, so that the result of the steering operation is prevented from becoming too sensitive, and the steering operation can be stabilized.

According to the fourth aspect of the present invention, the opening required for the power steering valve is regulated in inverse proportion to the running speed of the vehicle body. The straightness during traveling can be improved.

According to the fifth aspect of the present invention, since the return port of the power steering valve and the bleed-off port of the second flow control valve are connected via the bypass oil passage, the power steering is not used. In addition, the pressure oil that has passed through the power steering valve can be supplied to the lift control valve to increase the capacity of the lift cylinder.

[Brief description of the drawings]

FIG. 1 is a side view of a riding rice transplanter having a hydraulic circuit according to the present invention.

FIG. 2 is a hydraulic circuit diagram.

FIG. 3 is a bottom view of the steering mechanism.

FIG. 4 is a graph showing a relationship between an engine speed and a flow rate of hydraulic oil.

[Explanation of symbols]

 A Riding rice transplanter D Planting device H Hydraulic circuit P Hydraulic pump 30 Engine 31 First flow control valve 32 Second flow control valve 32b Bleed-off port 33 Left / right tilt control valve 34 Power steering valve 34r Return port 35 Elevation control valve 36 Bypass Oil passage

Claims (5)

[Claims] 1. A hydraulic pump (P) directly connected to an engine (30).
A hydraulic circuit for a riding rice transplanter, characterized in that first and second flow control valves (31) and (32) are connected in series on the discharge side. 2. A left-right inclination control valve (3) for controlling the left-right inclination of the planting device (D) between the first and second flow control valves (31) and (32).
3), and a power steering valve (34) and an elevation control valve 35 for controlling elevation of the planting device (D) are provided downstream of the first and second flow control valves (31) and (32). The hydraulic circuit for a riding rice transplanter according to claim 1, wherein the hydraulic circuit is connected. 3. A hydraulic oil flow supplied to the power steering valve (34) with a second flow control valve (32) interposed between the hydraulic pump (P) and the power steering valve (34). The hydraulic circuit of a riding rice transplanter according to claim 1 or 2, wherein an upper limit is set. 4. The opening degree of the power steering valve (34)
4. The hydraulic circuit for a riding rice transplanter according to claim 2, wherein the hydraulic circuit is regulated in inverse proportion to the running speed of the vehicle body. 5. A return port (34r) of the power steering valve (34) and a bleed-off port (32b) of a second flow control valve (32) are connected via a bypass oil passage (36). The hydraulic circuit for a riding rice transplanter according to any one of claims 2 to 4.